Noriega served as the Senior Policy Advisor and Alternate U.S. Representative at the U.S. Mission to the OAS from 1990 through 1993, and as Senior Advisor for Public Information at the OAS from 1993 to 1994.

Other tours of duty in the Department of State have been with the United States Agency for International Development (USAID) and the Bureaus for Inter-American Affairs and Public Affairs, where he was a Program Officer from 1987 through 1990 and a Senior Writer/Editor from 1986 until 1987. Prior to that, he served as Press Secretary and Legislative Assistant for Congressman Bob Whittaker (R-Kan.), U.S. House of Representatives, from 1983 until 1986. President Bush also appointed Noriega to the Board of Directors of the Inter-American Foundation.

In 2000, Noriega played a key role in the transition in Haiti following the overthrow of President Jean-Bertrand Aristide. Noriega was a vocal critic of the undemocratic actions undertaken by the Aristide government and represented the United States in public debates at the OAS about efforts to promote democracy and human rights in Haiti. Aristide's successor as president was the chief of the Supreme Court, in accordance with the Haitian Constitution. The Haitian Parliament chose Gerard Latortue as the new prime minister, who came to office despite the fact that he was living in Florida at the time. Amid rampant violence and chaos, Noriega worked with Brazil, Chile, and the United Nations to deploy the MINUSTAH peacekeeping mission to provide security until these internal security responsibilities could be assumed by Haiti's government. Noriega stated the U.S. Congress: "Now we can make a new beginning in helping Haiti to build a democracy that respects the rule of law and protects the human rights of its citizens." 7 After Noriega's involvement, Haiti has undergone a series of democratic transitions.[citation needed]

At the time of Posada Carriles' reported presence in the U.S. in 2005, Noriega stated that the United States government was not then aware of his presence, saying that the controversy over his presence in the country, "may be a completely manufactured issue," and that Posada "might not have been in the United States."[2]

Noriega was a major force behind the Bush Administration’s policy towards Cuba and Venezuela.[3]

In 1996, Noriega co-authored the Helms-Burton law which tightened the 40-year-old embargo on Cuba.[4]

In April 2002, Noriega was Ambassador to the OAS during the temporary ouster of Venezuelan president Hugo Chavez; although critics alleged U.S. support for the ouster, a Department of State investigation proved this allegations to be unsubstantiated.

Noriega resigned from the State Department in 2005 to join the private sector.[5] In 2009, he was hired as a U.S. lobbyist by an organization of the private sector of Honduras during the 2009 Honduran constitutional crisis when then President Manuel Zelaya was ousted for attempting to side step the Honduran constitution.[6] The private sector group sought to explain the origins of the constitutional ouster of Zelaya, who rendered himself ineligible for public office for defying the prohibition on reelection and sought to organize a plebiscite outside the framework of the Honduran constitution.

Since leaving office, Noriega has written on Western Hemisphere issues, including a claim that Iran has helped Venezuela start their own secret nuclear program.[7]